Controlled growth and interaction of NiCo2S4 on conductive substrate for enhanced electrochemical performance

The controlled nanostructure growth and its strong coupling with the current collector are key factors to achieve good electrochemical performance of faradaic-dominant electroactive materials. In this work, we demonstrate binder-less and additive-free hydrothermal and physical vapor doping methods for the synthesis of nickel cobalt sulfide (NiCo2S4) deposited on different conductive substrates such as pristine nickel foam (NF), reduced graphene oxide coated on NF (rGO/NF), and N-doped rGO coated on NF (N-rGO/NF). The size and density of NiCo2S4 nanosheets are controlled through the strong coupling with N-rGO/NF and rGO/NF. This controllable synthesis allows N-rGO/NF to achieve better electrochemical performance such as high capacity of 623.5 rnAh CI at 4 mA cm(-2), energy efficiency of 59.4% at 120 mA cm(-2), and cycling stability of 57% after 10,000 cycles than those of pristine NF and rGO/NF. These results are attributed to the synergy of controllably structured NICo2S4 nanosheets and strong interaction with conductive substrate.